Field of the Invention
The present invention relates to an image processing apparatus for extracting a frame of an output target from a plurality of frames constituting a moving image, an image processing method, and a storage medium.
Description of the Related Art
Conventional apparatuses including a moving-image replay function include a function for extracting, from a moving image, a still image constituting the moving image. Using a function of this type, when a user specifies a frame of an extraction target from a plurality of frames included in the moving image, an image of the specified frame is transmitted to a display device such as a liquid crystal monitor to be displayed thereon. In addition, the frame extracted from the moving image can be outputted to a print device to print the image corresponding to the frame on a print sheet.
Of the still images included in the moving image, the still image photographed when a hand of a photographer or an object moves may have a shake, and thus such an image may not be preferable as an output target. Japanese Patent Application Laid-Open No. 4301236 discusses a technique in which moving image data is analyzed to acquire an amount of shake of each frame included in the moving image, a reference frame is determined based on the acquired amount of the shake, and then peripheral frames within a predetermined range of the reference frame are output.
As a method for determining the amount of the shake of the image, the above-described conventional technique discusses a method for determining the amount of the shake based on an amount of movement, between the frames, of a feature point included in the frame.
However, even though the feature point included in the frame moves between the frames, it cannot be specified whether the feature point is moved due to the shake of a photographing apparatus or a movement of the object. Thus, even if the amount of the movement of the feature point between the frames is small and thus the amount of the shake of the characteristic point is small, the moving image may be photographed according to the movement of the object corresponding to the feature point. Further, at this point, even if the amount of the shake of the feature point is small, the amount of the shake of other region than the feature point in the frame may be large, and thus the frame may not be preferable as the output target.